Adjustable extension scaffold trestle with guard rail



Apri 8, 1941. H. c. BERCHEM ETAL 2,237,543

ADJUSTABLE EXTENSION SCAFFOLD TRESTLE WITH GUARD RAIL April 8, 1941 H. c. BERCHEM ETAL 2,237,543

ADJUSTABLE EXTENSION SCAFFOLD TRESTLE WITH GUARD RAIL I5 Sheets-Sheet 2 Filed Jan. 29, 1940 a `l s 6 4 April 8, 1941. 'H C. BERCHEM EVAL 2.237.543

ADJUSTABLE EXTENSION SCAFFOLD TRESTLE WITH GUARD RAIL Filed Jan. 29, 1940 3 Sheets-SheeL-''i 5 Patented Apr. 8, 1941 ice ADJUSTABLE EXTENSION SCAFFOLD TRESTLE WITH GUARD RAIL Hubert C. Berchem and John P. Schneider, St. Paul, Minn.

Application January 29, 1940, Serial No. 316,264

3 Claims. (Cl. S04- 7) Our invention relates to an improvement in a rail guarded adjustable scaffold trestle common- 1y used by painters, plasterers, carpenters,` etc., upon which a rail guarded platform is supported for workmen to stand.

While this invention relates to horse scaffolds, it deals more particularly to a rail guarded platform rigging having adjustability for the platform horse and the leg leveling devices, whereby the range of usefulness of this invention is greatly increased.

A more specific object of the invention is the providing of an adjustable horse scaffolded platform rigging with an elongatable guard rail and adjustable extensible leveling legs whereby the center of gravity of the horse will remain in the same line under all resting conditions; and whereby the workmen atop the platform supported by the scaffold trestle are protected by the elongatable rail which secures against falls While the level footing guards against the wobble of the horse under them.

Another object of the invention is to provide a platform rigging whose bearing surface is provided with a non-slippable material acting in conjunction with a pair of liftable and reversible plank-retaining dogs, to prevent any slippage or the sliding olf of the planks or platform from the platform bearing secured to the top of the interchangeable elevating unit.

Another object of the invention is to provide a novel and sturdy interchangeable elevating unit that may be changed from one of a little height to one of greater height should the demand arise.

With such objects in view and others which will appear in the following description, the novel features of construction and arrangement of parts will be set forth in these specicationsand the claims appended hereto.

The invention will be best understood by reference to the accompanying drawings which illustrate one embodiment of the invention and wherein similar characters of reference indicate corresponding parts in all views. In the drawings,

Figure 1 is a side elevation of our invention illustrating the extensible and adjustable construction of the same.

Figure 2 is a fragmental section of the supported platform taken on the line of 2 2 of Figure 1.

Figure 3 is an isometric drawing of the extensible horse trestle, illustrating the adjustability of the interchangeable frame.

Figure 4 is an illustration of a plank retaining dog and its pocket.

Figure 5 is a top view of an alternate scheme for elevation.

Figure 6 is a side elevation of Figure 5 partly broken away.

Figure 'l illustrates a permanent retention lil means for locking the interchangeable elevating unit to the horse.

Figure 8 is a partial perspective View illustrating the cam holding means employed in the construction illustrated in Figure 5.

Referring to the drawings A designates the body of a horse of common construction provided with a series of transverse horse ties B and longitudinal horse ties Bl securing the legs C into a rigid frame. The longitudinal horse ties Bl are provided with a series of upright guides D to act as guides for the interchangeable frame F.

The interchangeable frame F is composed of a series of vertical members M resting atop a bottom lifting memberN and supporting a platform rigging member R. atop the same. The platform rigging member R is provided with a nonslipping top T secured atop said member and the p ya main stem X3, a wing member Xl with a top face X2.

The vertical members M of the interchangeable frame F are further provided with a series of rungs W which provide the interchangeable elevating unit with stepping possibilities, such as a ladder, permitting the rungs B of the horse A to act as the yfoot rungs, while the rungs W of the interchangeable elevating unit act as the intermediate elevating ladder extension to the platform.

The top of the horse A is provided with a series of bearings Y through which is passed the shaft Z upon which is secured the handled crank K. The shaft Z is provided with the lifting cable fastening means XI affording the cable 2 a winding support Z2 which is secured at the bottom through the elevating base member N of the interchangeable elevating unit F by a knot 3.

The top rail R supported by the vertical members M is provided at its ends with a series of U shaped brackets 4 secured by fastening means 5 to the rail R. The Vertical members M of the interchangeable elevating unit F are further provided with drop stops F5 which likewise act as rail stave positioning blocks. The U shaped brackets 4 extending out from the rigging member R pro-y vide orifices l into which the rail stave 8 of the extensible rail are positioned while the rail stave 8 is further provided with a series of guard rails 9 secured thereto.

At the free end of the guard rails 9 there is provided a locking stave I!! secured so that the guard rail in its entirety is held in locked position at its limits of extension; permitting extension to any intermediate position, the rail stave 8a supporting a counter part to the rail stave 8 affording means for the rails da which are provided with a rail locking stave Illa to the length of the rail staves 8 or 81a and permitting the placement of another adjustable trestle horse at mid-position to supportthe said platform P.

The vertical members M of the interchangeable elevating unit F are further provided on their y sides opposite the interchangeable elevating units lifting mechanism with inset lock strips II secured to the vertical members M by holding means I2. The lock strips II are further provided with a series of indentures or cutouts I3 spaced to bring the indentures in parallel alignment with each other.

To the top of the horse, on one side of the lock strip there is provided a lock bar Iii which is connected through the hinges I5 to the top face I6 of the horse proper. rThe lock bar I 4 is further provided with a control handle I'I to tip the lock bar I4 into and out of engagement. The lock strip I4 is further provided with cutouts I8 and locking lugs I9. These cutouts I8 and locking lugs I9 are so positioned as to register with the locking holes I3 of the member II.

In Figure 5, showing an alternate elevating means, the handle K secured to the shaft Z supported in bearings Y is provided with a pair of pinions which cooperate with an inset rack 2| gained into the vertical pinion side of the member M of the interchangeable frame F. The locking mechanism for this alternate scheme, consists of a pair of tippable dogs 22 secured in supports 23 fastened onto the side of the top transverse tie member B of the horse so that the dogs teeth will register with and seat within the space between the teeth of the rack ZI at the elevation desired.

The horse legs C are each provided with inset threaded female seats 24 into which are screwed the adjusting screw members 25. The adjusting screw members 25 are adjustable by the turning of the knurled adjusting wheel 26 which seat the wobble leg 2'! solidly upon the floor.

Should it be desired to lock the interchangeable elevating unit F within the horse A for any given time, a rod 23 supplied with washers 29 and lock nuts 30 is passed through the orice 3| in the longitudinal stay members BI and thence through the orifices 32 of the interchangeable elevating unit F and then through the opposite orifices 32 and 3| to rigidly lock the assembly as best illustrated in Figure 7.

In operation, the assembled horse A is equipped with an interchangeable elevating unit F having its liftable cables 2 secured at one end in the knot 3 on the under side for the lifting member N and the upper cable end locked upon the rotatable shaft Z through its cable fastening Zi. The clockwise rotation of the handled crank K will Wind the lifting cable 2 upon the shaft Z and thereby elevate the interchangeable elevating unit F traveling within its guides D. The guides D are secured to the longitudinal stays BI in a perfect vertical position. When a predetermined height of elevation has been secured thus enabling a true vertical lift for the interchangeable elevating unit, the lock strip I4 through its control handle I'I is leveled so that the locking dogs I9 will register Within one set of the series of parallel holes I3 of the vertical locking members II of the upright members M of the interchangeable elevating unit F.

The planks are then placed upon the top of the non-slipping face T of the horizontal rigging member R and the dogs X are then lifted from out of their recesses T and reversed so that the portion XI of the reversible dogs rests upon the top non-slipping surface T as best illustrated in Figure 3. 'Ihe dogs X thereby forming an obstruction, preventing the platform P from sliding off from the platform rigging member R after the several horses, platform or planking have been positioned, the telescoping rail assembly is extended so that the rail staves 8 and 8a can be placed within the orifices 'I of the U shaped brackets 4 extending out from the rigging member R as best illustrated in Figure l and Figure 6.

The horse A because of its several longitudinal and transverse stays B form a stepladder While the interchangeable elevating unit F equipped with rungs W will form a ladder extension to enable the workmen to mount the platform without diiculty.

I claim:

l. An adjustable trestle comprising a rigid scaffold horse supporting a series of vertical side rail guides, an interchangeable elevatable trestle unit slidable within said side rail guides, a 'winch secured atop said rigid scaffold horse, a series of lifting cables secured to the winch and to the interchangeable liftable unit, a series of locking members secured in the vertical members or" the interchangeable liftable unit, and a hinged locking strip provided with positioned locking dogs cooperating with the locking strip within the vertical members of the interchangeable liitable trestle unit top provided with a non-slipping surface member, and a series of reversible staging holding dogs extending down therethrough and into said interchangeable liftable trestle unit to member.

2. An adjustable scaffold trestle comprising a rigid scaffold horse supporting a series of vertical side rail guides, an interchangeable elevatable trestle unit slidable through the top of the rigid scaffold horse and within the side rail guides of the scaffold horse, said interchangeable elevatable trestle unit being provided with a platform member, a nonslidable top member for said platform member, and a series of staging holding dogs or pegs extending down through the nonslidable top member and into the said platform member so as to prevent the slipping off of a platform supported upon said platform member.

3. An apparatus of the class described including an elevatable trestle slidable within vertical side guides supported in a rigid trestle horse, a platform member upon the elevatable trestle, a non-slipping member atop said platform member, said platform member having a set of reversible staging holding dogs or pegs extending down through the non-slipping top member into said platform member so to prevent the staging from slipping from the platform member, and

- a telescoping side guard rail extending above elevated platform member and wholly supported upon the end of the platform member.

HUBERT C. BERCHEM. JOHN P. SCHNEIDER, 

